Multisectional insulators for electrical heaters have been known for many years. For instance, Hynes U.S. Pat. No. 2,790,889 discloses a fluid electric heater including a cluster of resistor ribbons which are supported by a plurality of spaced-apart, gear-like insulators. Each of the gear-like insulators cooperates with a corresponding group of insulator clips to clamp a portion of each of the resistor ribbons therebetween. Each of the clips has a recess in its outer edge for receiving a band extending around all of the clips of a corresponding group to hold them in place. The gear-like insulators are supported by a central rod or tube. The electric heater is contained in a tubular housing, which may be disposed vertically or horizontally. The clips function to prevent the resistor ribbons, which act as heating elements when energized, from contacting the housing, through which a fluid to be heated passes.
Because the resistor ribbons are gripped and supported by the gear-like insulators and the insulator clips, the natural expansion and contraction of the resistor ribbons are inhibited. Inhibiting such expansion and contraction can result in the breakage of the resistor ribbons. Also, inasmuch as the gear-like insulators and the insulator clips do not completely insulate each resistor ribbon from its adjacent resistor ribbons, the electric heater of the Hynes '889 patent suffers from the further disadvantage that its operation could be deleteriously affected by adjacent resistor ribbons coming into contact with each other, for instance, if they are heated to a temperature sufficiently high to cause them to become soft and deformable. If the resistor ribbons come into contact with each other, shorting and resistor ribbon failure could result.
Hynes U.S. Pat. Nos. 2,963,539 and 3,441,712 disclose electrical resistor heaters employing insulators which are somewhat similar to the insulators described and illustrated in the Hynes '889 patent. Like the insulators of the Hynes '889 patent, the insulators of the Hynes '539 and '712 patents grip and support resistors passing therethrough and, therefore, suffer from at least one of the above-described problems of the electric heater disclosed in the Hynes '889 patent.